python - 如何在 django 模型/视图中计算总和

问题描述

我正在尝试为学生制作结果应用程序，有两种模型，一种用于学科，一种用于课程，每门课程都有不止一个具有学科学分的学科，所以我想总结所有学科学分取决于课程，现在我' m 获得单门课程的总科目学分，但是否可以拥有所有课程的科目总学分？因为他/她可以有不止一门课程。例如，一门课程的科目总学分 = 12 另一个学分 = 8 .......所以总学分 = 20 学分请看图片以及第二个图像模型设计的更好方法

模型.py

    class Subject(models.Model):
       user = models.ForeignKey(
                      settings.AUTH_USER_MODEL, on_delete=models.CASCADE, null=True)
       name = models.CharField(max_length=50)
       code = models.PositiveIntegerField(unique=True)
       credit = models.IntegerField(blank=True)
       files = models.FileField(upload_to='course/materials/', blank=True)
       status = models.CharField(max_length=15, choices=Subject_Status, blank=True)

    def __str__(self):
        return self.name
        

    class Meta:
        db_table = ''
        managed = True
        verbose_name = 'Subject'
        verbose_name_plural = 'Subjects'


    class Course(models.Model):
         user = models.ForeignKey(
              settings.AUTH_USER_MODEL, on_delete=models.CASCADE, null=True)
         name = models.CharField(max_length=200, unique=True)
         prefix = models.CharField(max_length=20)
         code = models.CharField(max_length=20)
         subject = models.ManyToManyField('Subject', related_name='subject_list', blank=True)

         faield = models.ManyToManyField(Subject,related_name='failed_subject_status', blank=True)
         passed = models.ManyToManyField(Subject,related_name='passed_subject_status', blank=True)
         nerver = models.ManyToManyField(Subject,related_name='never_subject_status', blank=True)
         current = models.ManyToManyField(Subject,related_name='curent_subject_status', blank=True)
    
         program = models.ForeignKey('Program', related_name='program_course', on_delete=models.CASCADE, 
                                    blank=True, null=True)

视图.py

    class Program_structure(generic.View):

        def get(self, *args, **kwargs):
            profile = Student.objects.all()
            program_structure = Course.objects.filter(user=self.request.user)
            credit = 
              Course.objects.filter(user=self.request.user).annotate(total_credit=Sum('subject__credit'))

           context = {
            'test':program_structure,
            'credit':credit,         #this is giving single course total 
            'profile':profile,

           }
            return render(self.request, 'test.html', context)

标签： pythonpython-3.xdjangodjango-modelsdjango-views

python - 如何在 django 模型/视图中计算总和

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